then in your body anything placed between:
<div id="MainDiv">your stuff</div>
will adhere to those settings, play around with the numbers to create any margins you wish.(in IE or NS 4+)

Just remember that if you access anything in that div via Netscape you will have to mention where it is , ie - if you have a form in that div you would access it by document.MainDiv.document.formname.fieldname.value.

If you use the following attributes inside your body tag, bottommargin="0" leftmargin="0" marginheight="0" marginwidth="0" rightmargin="0" topmargin="0". This will make your borders 0 in NS 4+ and IE 3+. Just a warning, Netscape 3 does not recognize these tags and you will have a border of about 10 pixels all around. There is nothing you can do about this.